Biomedical subjects

J C Gardiner

Publications and source records attributed to J C Gardiner.

At least 19 recordsLinked to original sources

PubMed2001

A comparison of the effects of lamotrigine on neuroma-induced action potential firing and normal behaviour in rat: implications for establishing a pre-clinical 'therapeutic index'.

The effects of lamotrigine on rat neuroma and behavioural paradigms were evaluated to determine a pre-clinical therapeutic index. Lamotrigine blocked neuroma-induced burst pattern firing at a free plasma concentration of 13.7+/-1.7 microM (n=5). Oral dosing of lamotrigine (50-200 mg/kg) had no significant effects on behaviour but measurements of plasma concentrations of free drug showed non-linear oral absorption and lower than predicted drug levels (5-27 microM). Given intravenously (10-100 mg/kg), lamotrigine did affect behaviour at a free plasma concentration of 42.0 microM (n=2). By comparing free plasma concentrations, a therapeutic index of 3 was calculated, which is lower than published data based on comparing oral doses. We propose that a therapeutic index should only be derived with reference to plasma drug concentrations to prevent non-linear or incomplete drug absorption from confounding accurate estimation.

Action Potentials↗

PubMed2001

Strain in the human medial collateral ligament during valgus loading of the knee.

The medial collateral ligament is one of the most frequently injured ligaments in the knee. Although the medial collateral ligament is known to provide a primary restraint to valgus and external rotations, details regarding its precise mechanical function are unknown. In this study, strain in the medial collateral ligament of eight knees from male cadavers was measured during valgus loading. A material testing machine was used to apply 10 cycles of varus and valgus rotation to limits of +/- 10.0 N-m at flexion angles of 0 degrees, 30 degrees, 60 degrees, and 90 degrees. A three-dimensional motion analysis system measured local tissue strain on the medial collateral ligament surface within 12 regions encompassing nearly the entire medial collateral ligament surface. Results indicated that strain is significantly different in different regions over the surface of the medial collateral ligament and that this distribution of strain changes with flexion angle and with the application of a valgus torque. Strain in the posterior and central portions of the medial collateral ligament generally decreased with increasing flexion angle, whereas strain in the anterior fibers remained relatively constant with changes in flexion angle. The highest strains in the medial collateral ligament were found at full extension on the posterior side of the medial collateral ligament near the femoral insertion. These data support clinical findings that suggest the femoral insertion is the most common location for medial collateral ligament injuries.

Cadaver↗

PubMed2001

Screening for high utilizing somatizing patients using a prediction rule derived from the management information system of an HMO: a preliminary study.

BACKGROUND: Somatization is a common, costly problem with great morbidity, but there has been no effective screening method to identify these patients and target them for treatment. OBJECTIVES: We tested a hypothesis that we could identify high utilizing somatizing patients from a management information system (MIS) by total number of visits and what we termed "somatization potential," the percentage of visits for which ICD-9 primary diagnosis codes represented disorders in the musculoskeletal, nervous, or gastrointestinal systems or ill-defined complaints. METHODS: We identified 883 high users from the MIS of a large staff model HMO as those having six or more visits during the year studied (65th percentile). A physician rater, without knowledge of hypotheses and predictors, then reviewed the medical records of these patients and identified somatizing patients (n = 122) and nonsomatizing patients (n = 761). In two-thirds of the population (the derivation set), we used logistic regression to refine our hypothesis and identify predictors of somatization available from the MIS: demographic data, all medical encounters, and primary diagnoses made by usual care physicians (ICD-9 codes). We then tested our prediction model in the remaining one-third of the population (the validation set) to validate its usefulness. RESULTS: The derivation set contained the following significant correlates of somatization: gender, total number of visits, and percent of visits with somatization potential. The c-statistic, equivalent to the area under the ROC curve, was 0.90. In the validation set, the explanatory power was less with a still impressive c-statistic of 0.78. A predicted probability of 0.04 identified almost all somatizers, whereas a predicted probability of 0.40 identified about half of all somatizers but produced few false positives. CONCLUSIONS: We have developed and validated a prediction model from the MIS that helps to distinguish chronic somatizing patients from other high utilizing patients. Our method requires corroboration but carries the promise of providing clinicians and health plan directors with an inexpensive, simple approach for identifying the common somatizing patient and, in turn, targeting them for treatment. The screener does not require clinicians' time.

Adult↗

PubMed2001

A 90-kD phospholipase D from tobacco binds to microtubules and the plasma membrane.

The organization of microtubule arrays in the plant cell cortex involves interactions with the plasma membrane, presumably through protein bridges. We have used immunochemistry and monoclonal antibody 6G5 against a candidate bridge protein, a 90-kD tubulin binding protein (p90) from tobacco BY-2 membranes, to characterize the protein and isolate the corresponding gene. Screening an Arabidopsis cDNA expression library with the antibody 6G5 produced a partial clone encoding phospholipase D (PLD), and a full-length gene was obtained by sequencing a corresponding expressed sequence tag clone. The predicted protein of 857 amino acids contains the active sites of a phospholipid-metabolizing enzyme and a Ca(2+)-dependent lipid binding domain and is identical to Arabidopsis PLD delta. Two amino acid sequences obtained by Edman degradation of the tobacco p90 are identical to corresponding segments of a PLD sequence from tobacco. Moreover, immunoprecipitation using the antibody 6G5 and tobacco BY-2 protein extracts gave significant PLD activity, and PLD activity of tobacco BY-2 membrane proteins was enriched 6.7-fold by tubulin-affinity chromatography. In a cosedimentation assay, p90 bound and decorated microtubules. In immunofluorescence microscopy of intact tobacco BY-2 cells or lysed protoplasts, p90 colocalized with cortical microtubules, and taxol-induced microtubule bundling was accompanied by corresponding reorganization of p90. Labeling of p90 remained along the plasma membrane when microtubules were depolymerized, although detergent extraction abolished the labeling. Therefore, p90 is a specialized PLD that associates with membranes and microtubules, possibly conveying hormonal and environmental signals to the microtubule cytoskeleton.

Amino Acid Sequence↗

PubMed2001

Simple shear testing of parallel-fibered planar soft tissues.

The simple shear test may provide unique information regarding the material response of parallel-fibered soft tissues because it allows the elimination of the dominant fiber material response from the overall stresses. However, inhomogeneities in the strain field due to clamping and free edge effects have not been documented. The finite element method was used to study finite simple shear of simulated ligament material parallel to the fiber direction. The effects of aspect ratio, clamping prestrain, and bulk modulus were assessed using a transversely isotropic, hyperelastic material model. For certain geometries, there was a central area of uniform strain. An aspect ratio of 1:2 for the fiber to cross-fiber directions provided the largest region of uniform strain. The deformation was nearly isochoric for all bulk moduli indicating this test may be useful for isolating solid viscoelasticity from interstitial flow effects. Results suggest this test can be used to characterize the matrix properties for the type of materials examined in this study, and that planar measurements will suffice to characterize the strain. The test configuration may be useful for the study of matrix, fiber-matrix, and fiber-fiber material response in other types of parallel-fibered transversely isotropic soft tissues.

Ligaments↗

PubMed2001

Impairments of memory and learning in older adults exposed to polychlorinated biphenyls via consumption of Great Lakes fish.

An association between in utero polychlorinated biphenyl (PCB) exposure and impaired childhood intellectual functioning has been reported, but the potential impact of PCB exposure during adulthood on intellectual functioning has received little attention. We assessed the impact of PCBs and other fish-borne contaminants on intellectual functioning in older adults. The subjects were 49- to 86-year-old Michigan residents recruited from an existing cohort. Fish eaters ate > 24 lb of sport-caught Lake Michigan fish per year and non-fish eaters ate < 6 lb of Lake Michigan fish per year. A battery of cognitive tests including tests of memory and learning, executive function, and visual-spatial function was administered to 180 subjects (101 fish eaters and 79 non-fish eaters). Blood samples were analyzed for PCBs and 10 other contaminants. We evaluated cognitive outcomes using multiple regression. PCBs and dichlorodiphenyl dichloroethene (DDE) were markedly elevated in fish eaters. After controlling for potential confounders PCB, but not DDE, exposure was associated with lower scores on several measures of memory and learning. These included the Weschler Memory Scale verbal delayed recall (p = 0.001), the semantic cluster ratio (p = 0.006), and list A, trial 1 (p = 0.037), from the California Verbal Learning Test. In contrast, executive and visual-spatial function were not impaired by exposure to either PCBs or DDE. In conclusion, PCB exposure during adulthood was associated with impairments in memory and learning, whereas executive and visual-spatial function were unaffected. These results are consistent with previous research showing an association between in utero PCB exposure and impairments of memory during infancy and childhood.

Aged↗

PubMed2001

Computational modeling of ligament mechanics.

This article provides a critical review of past and current techniques for the computational modeling of ligaments and tendons. A brief overview of relevant concepts from the fields of continuum mechanics and finite element analysis is provided. The structure and function of ligaments and tendons are reviewed in detail, with emphasis on the relationship of microstructural tissue features to the continuum mechanical hehavior. Experimental techniques for the material characterization of biological soft tissues are discussed. Past and current efforts related to the constitutive modeling of ligaments and tendons are classified by the particular technique and dimensionality. Applications of one-dimensional and three-dimensional constitutive models in the representation of the mechanical behavior of joints are presented. Future research directions are identified.

Animals↗

PubMed2001

The effect of subclinical Mycobacterium paratuberculosis infection on milk production in Michigan dairy cows.

The objective of this study was to determine the effect of subclinical Mycobacterium paratuberculosis infection on mature equivalent milk, protein, and fat production in a sample of Michigan dairy herds with a history of cows positive for M. paratuberculosis diagnosed by fecal culture. A prospective two-group cohort study was conducted. Participating herds were tested, and productivity and reproduction records were monitored for 18 mo. All cows aged 24 mo and greater were tested for M. paratuberculosis infection using the ELISA and radiometric fecal culture (RFC) techniques. Using both tests in parallel, the overall sample apparent prevalence for M. paratuberculosis infection was 41.8%. Adjusting for diagnostic sensitivity and specificity resulted in a calculated sample true prevalence of 59.9%. Subclinical paratuberculosis test-positive status had no statistically significant effect on mature equivalent milk, fat, or protein production. The results of this study concur with the findings of other studies, reporting that the magnitude and direction of the association between subclinical paratuberculosis infection and milk production depends upon the parity of the animal, stage of disease, and the stage in lactation being monitored. Assessment of the impact of subclinical paratuberculosis on milk production must consider the average parity of the sample population. In herds that have an average parity of 2 or less, subclinical paratuberculosis infection may have little impact on milk production.

Animals↗

PubMed2000

The effect of subclinical Mycobacterium paratuberculosis infection on days open in Michigan, USA, dairy cows.

A prospective cohort study design was used to evaluate the impact of subclinical Mycobacterium paratuberculosis infection on days open in a sample of Michigan dairy herds with a history of cows positive for M. paratuberculosis diagnosed by fecal culture. Participating herds were tested and productivity and reproduction records were monitored for 18 months. All cows > or = 24 months old were tested for M. paratuberculosis infection using the ELISA and radiometric fecal-culture (RFC) techniques. Test-negative cows were re-tested at the conclusion of the monitoring period. Multivariable regression models were used. Using both tests in parallel, the overall sample apparent prevalence for M. paratuberculosis infection was 41.8% (223/533 animals tested). Adjusting for diagnostic sensitivity and specificity, this resulted in a calculated sample true prevalence of 59.9%. ELISA-positive cows (on average) had a 28-day increase in days open when compared to ELISA-negative cows (p=0.02). The diagnostic method used to define a case altered the apparent association between paratuberculosis test status and days open. Fecal culture was a less-effective diagnostic tool for use in herds with a high prevalence of infected animals. The increase in days open in the ELISA-positive cows was an indication that perhaps reduced estrus expression or an increased post-partum anestrous period occurred in the subclinically infected ELISA-positive animals. This might have been due to a negative energy balance associated with M. paratuberculosis infection.

Animals↗

PubMed2000

Power and sample assessments for tests of hypotheses on cost-effectiveness ratios.

We address the issue of statistical power and sample size for cost-effectiveness studies. Tests of hypotheses on the cost-effectiveness ratio (CER) are constructed from the net cost and incremental effectiveness measures. When the difference in effectiveness is known, we derive formulae for statistical power and sample size assessments for one- and two-sided tests of hypotheses of the CER. We also construct a test of the joint hypothesis of cost-effectiveness and effectiveness and derive an expression connecting power and sample size. Our methods account for the correlation between cost and effectiveness and lead to smaller sample size requirements than comparative methods that ignore the correlation. The implications of our formulae for cost-effectiveness studies are illustrated through numerical examples. When compared with trials designed to demonstrate effectiveness alone, our results indicate that a trial appropriately powered to demonstrate cost-effectiveness might require sample sizes many times greater.

Confidence Intervals↗

PubMed2000

Evidence-based guidelines for teaching patient-centered interviewing.

In a rare study of effectiveness of an interviewing method, we previously reported a randomized controlled trial demonstrating that training in a step-by-step patient-centered interviewing method improved residents' knowledge, attitudes, and skills and had a consistently positive effect on trained residents' patients. For those who wish to use this evidence-based patient-centered method as a template for their own teaching, we describe here for the first time our training program--and propose that the training can be adapted for students, physicians, nurse practitioners, physician assistants, and other new learners as well. Training was skills-oriented and experiential, fostered positive attitudes towards patient-centered interviewing, and used a learner-centered approach which paid special attention to the teacher-resident relationship and to the resident's self-awareness. Skills training was guided by a newly identified patient-centered interviewing method that described the step-by-step use of specific behaviors.

Attitude of Health Personnel↗

PubMed2000

Impact of a deep saturation dive on semen quality.

The demonstration dive 'Aurora' has provided an opportunity to study the impact of extreme hyperbaric conditions on male fertility. This operation involved a 33-day diving programme during which divers were exposed to a maximum pressure of 4.6 Mega Pascals (Mpa) for 7 days. At days - 4, + 27, + 34, + 82 and + 263 relative to the initiation of the dive, semen samples were analysed to determine the quality of spermatogenesis and the functional competence of the spermatozoa. A dramatic fall in semen quality was observed in association with the dive and by day + 82 the potential fertility of the men was seriously compromised as evidenced by oligoasthenoteratozoospermic semen profiles and the poor fertilizing potential of the spermatozoa. These studies indicate, for the first time, that the severe hyperbaric conditions associated with deep saturation dives have a profound effect on male reproductive function.

Diving↗

PubMed2000

Why most workers with occupational repetitive trauma do not file for workers' compensation.

Despite the availability of no fault insurance for wage replacement and medical care costs, the majority of workers diagnosed with an occupational disease do not apply for workers' compensation. The objective of the study was to determine the reasons why workers diagnosed with work-related musculoskeletal disease did not apply for workers' compensation benefits. A cross-sectional study of 1598 individuals diagnosed with neck, upper extremity, and low back work-related musculoskeletal disease from April to June 1996 was performed. All individuals were interviewed over the telephone using a standardized questionnaire. The questionnaire included questions about the precipitating event; demographics; health limitations; mood; pain level; and attitudes toward their health care provider, fellow workers, management, work environment, and filing for workers' compensation. Whenever possible, standardized questions from previous surveys were used. The interviewed individuals with work-related musculoskeletal disease were reported by health care practitioners as required by the state of Michigan's occupational disease reporting law. Workers reported during 12 weeks in the spring of 1996 by a Michigan health care professional as having a neck, back, or upper extremity musculoskeletal disorder were eligible to participate. Among the 2703 reports received, 490 individuals could not be reached, 22 did not speak English, 12 had died or were too incapacitated by other medical conditions, and 581 refused. We interviewed 59% of all eligible workers and 73% of all workers who were reachable and capable of responding in English. Only 25% of workers diagnosed with musculoskeletal disease filed a workers' compensation claim. The factors significantly associated with filing a claim were (1) increased length of employment (> 21 years: odds ratio [OR], 3.01, 95% confidence interval [CI], 1.31 to 6.90); 11 to 20 years: OR, 2.34, 95% CI, 1.01 to 5.47; 6 to 10 years: OR, 1.76, 95% CI, 0.73 to 4.25; 1 to 5 years: OR, 2.36, 95% CI, 1.03 to 5.42; < 1 year: OR, 1.00; (2) lower annual income (< $40,000: OR, 1.75, 95% CI, 1.06 to 2.88 vs > or = $80,000: OR, 1.00); (3) workers' dissatisfaction with coworkers (OR, 1.76, 95% CI, 1.01 to 3.06); (4) physician restrictions on activity (OR, 2.16, 95% CI, 1.55 to 3.00); (5) type of physician providing treatment (specialist, including surgeon or orthopedist: OR, 3.63, 95% CI, 2.37 to 5.55); physical and occupational therapist: OR, 2.15, 95% CI, 1.35 to 3.43); family practitioner: OR, 1.33, 95% CI = 0.89 to 2.01; company physician: OR = 1.00); (6) off work > or = 7 days (OR, 14.85, 95% CI, 10.57 to 20.85); (7) decreased current health status (OR, 0.82, 95% CI, 0.70 to 0.96); and (8) increased severity of illness (OR, 1.24, 95% CI, 1.06 to 20.88). This study showed that only 25% of workers with a work-related musculoskeletal condition filed for workers' compensation and refutes the common perception that an individual with a work-related problem is likely to file a workers' compensation claim. The strongest predictors of who would file were those factors associated with the severity of the condition. Other factors were increasing length of employment, lower annual income, and worker dissatisfaction with coworkers. Our study population consisted mainly of unionized autoworkers, and our findings may not be generalizable to the total workforce.

Adolescent↗

PubMed2000

PCB congener profile in the serum of humans consuming Great Lakes fish.

The State of Michigan has a long history of research into human exposure to environmental contaminants through consumption of recreationally caught fish. A large cohort of Lake Michigan residents who eat fish (fish-eaters) and those who do not eat fish (nonfish-eaters) established in 1980 served as the basis for the congener-specific polychlorinated biphenyl (PCB) exposure evaluation reported here. In this paper we present the serum PCB congener profile for a subset of this cohort who were over 50 years of age. Serum samples were collected in 1993-1995 and were evaluated by a dual column capillary column gas chromatography procedure capable of detecting over 90 PCB congeners. This evaluation demonstrated significant PCB exposure in the fish-eaters (mean serum PCB of 14.26 ppb; n = 101). This elevated exposure allowed the establishment of a detailed profile of the PCB congeners found in humans exposed by this route. Twenty-two congeners of varying concentrations were the most prevalent and constituted over 95% of the total PCB present in most subjects. Four congeners, 138/163 (2,2',3,4,4',5-PCB/2,3,3',4', 5,6-PCB), 180 (2,2',3,4,4',5,5'-PCB), and 153 (2,2',4,4',5,5'-PCB), accounted for 55-64% of the total PCB load. Other congeners, some of toxicologic significance, were also detected by this analytical protocol. Nonfish-eaters had lower total serum PCB levels (mean = 4. 56; n = 78), but the same general pattern of PCB congeners was present. It was demonstrated that careful selection of a subset of prevalent PCB congeners could provide a cost-effective assessment of exposure without losing critical scientific information.

Aged↗

PubMed1999

Phenobarbital compared with phenytoin for the treatment of neonatal seizures.

BACKGROUND: Seizures occur in 1 to 2 percent of neonates admitted to an intensive care unit. The treatment is usually with either phenobarbital or phenytoin, but the efficacy of the two drugs has not been compared directly. METHODS: From 1990 to 1995, we studied 59 neonates with seizures that were confirmed by electroencephalography. The neonates were randomly assigned to receive either phenobarbital or phenytoin intravenously, at doses sufficient to achieve free plasma concentrations of 25 microg per milliliter for phenobarbital and 3 microg per milliliter for phenytoin. Neonates whose seizures were not controlled by the assigned drug were then treated with both drugs. Seizure control was assessed by electroencephalographic criteria. RESULTS: Seizures were controlled in 13 of the 30 neonates assigned to receive phenobarbital (43 percent) and 13 of the 29 neonates assigned to receive phenytoin (45 percent; P=1.00). When combined treatment is considered, seizure control was achieved in 17 (57 percent) of the neonates assigned to receive phenobarbital first and 18 (62 percent) of those assigned to receive phenytoin first (P=0.67). The severity of the seizures was a stronger predictor of the success of treatment than was the assigned agent. Neonates with mild seizures or with seizures that were decreasing in severity before treatment were more likely to have their seizures end, regardless of the treatment assignment. CONCLUSIONS: Phenobarbital and phenytoin are equally but incompletely effective as anticonvulsants in neonates. With either drug given alone, the seizures were controlled in fewer than half of the neonates.

Anticonvulsants↗

PubMed1999

Factors influencing recovery from and duration of lameness in Michigan (USA) horses.

The objective of this study was to identify factors that may affect recovery from and duration of a case of lameness in a stratified random sample of Michigan horses. This was done using data from Phase-II of the Michigan equine monitoring system (MEMS Phase-II), the equine health-monitoring study [Kaneene et al., Prev. Vet. Med. 29 (1997b) 277-292; Ross and Kaneene, Prev. Vet. Med. 28 (1996a) 209-224; Ross and Kaneene, Prev. Vet. Med. 29 (1996b) 59-75; Ross et al., Am. J. Vet. Res. 59 (1997) 23-29]. In this study, statistical modelling was conducted to evaluate risk factors affecting recovery from and duration of lameness using multivariable logistic regression and Cox's proportional hazards regression, respectively. Of 357 incident lameness cases reported during MEMS Phase-II, 280 (78.6%) were reported to have recovered. The median duration of a lameness case was 18 days (1st quartile (Q): 1, maximum (Max): 360). A total of 296 of 357 (82.9%) incident lameness cases received some type of treatment. Of 619 total treatments used, 329 (53.2%) were administered, conducted or applied by a veterinarian. Horses experiencing other types of lameness were less likely to recover than those experiencing hoof lameness (odds ratio (OR) = 0.48; 95% CI: 0.25, 0.93). Horses that had participated in exercise-related activities during the study period and prior to the lameness were more likely to recover (OR = 1.91; 95% CI: 1.05, 3.50). Treatment of the lameness was associated with an increased likelihood of recovery (OR = 1.82; 95% CI: 0.97, 3.45). Cases with a veterinarian involved in the diagnosis were associated with a decreased risk of recovery (OR = 0.48; 95% CI: 0.27, 0.84) and a longer duration lameness (HR = 0.58; 95% CI: 0.45, 0.73)--which might indicate that these cases were more complex or severe. Although cases treated for lameness were more likely to recover (OR = 1.82; 95% CI: 1.05, 3.50), treatment was not associated with lameness duration (HR = 0.58; 95% CI: 0.45, 0.73).

Animals↗

PubMed1999

Diagnosis of attention-deficit/hyperactivity disorder and use of psychotropic medication in very young children.

CONTEXT: Increases in diagnosis and treatment of attention-deficit/hyperactivity disorder (ADHD) have elicited public and professional concern. Research suggests that this trend warrants the inclusion of previously underdiagnosed children and adults. It is not clear whether this trend includes young children. OBJECTIVE: To identify patterns of diagnosis and treatment of ADHD in very young children over time. DESIGN: Descriptive study of Michigan Medicaid claims data. PATIENTS: Inclusion criteria included recorded ADHD diagnosis, continuous Medicaid eligibility during a 15-month period, and age 3 years or younger at the first date of service. MAIN OUTCOME MEASURES: Diagnoses of ADHD, conditions commonly comorbid with ADHD, other chronic health conditions, and injuries; treatments such as psychological services and psychotropic medication; and the number of ambulatory visits. RESULTS: We identified 223 children aged 3 years or younger diagnosed with ADHD. Many had conditions commonly comorbid with ADHD (44%), other chronic health conditions (41%), and injuries (40%). More than half received psychotropic medication (57%); fewer received psychological services (27%). Twenty-two different psychotropic medications were used. Patterns included more than 1 psychotropic medication (46%) in 30 combinations of simultaneous use and 44 combinations of sequential use. The mean number of ambulatory visits was 18. CONCLUSIONS: Children aged 3 years or younger had ADHD diagnosed and received markedly variable psychotropic medication regimens. Little information is available to guide these practices. The presence of comorbid conditions and injuries attests to these children's vulnerability. Resources must be identified that will enable physicians to better respond to the compelling needs of these children and their families.

Age Factors↗

PubMed1999

Motor function in aging Great Lakes fisheaters.

Exposure to contaminants in Great Lakes fish has been linked to impaired neuropsychological functioning in children, but neurological function of exposed adults has not been evaluated. This report describes a cross-sectional analysis of the effects of PCB/DDE exposure from contaminated fish on fine motor function in older adults. The subjects were 50-90-year-old Michigan residents who were members of a previously established study cohort. Fisheaters ate 24 lbs or more of sport-caught Lake Michigan fish/year at the time they were originally recruited in 1980-1982. Age- and sex-matched non-fisheaters ate 6 or fewer lbs/year. Outcome measures were scores on the Static Motor Steadiness Test (SMST) and Grooved Pegboard Test (GPT). PCB/DDE exposure was determined through serum analyses performed at the time of recruitment into the present study in 1993-1995. Because of the high correlation between serum PCB and DDE levels in this sample (Spearman r=0.64, P<0.0001), the effects of the two contaminants were assessed jointly using a single derived exposure variable=Low=both PCB and DDE at or below the medians of their respective distributions, intermediate=PCB and/or DDE in the third quartile, and high=PCB and/or DDE in the upper quartile. In unadjusted analyses, high exposure to PCBs/DDE was associated with significantly poorer performance on the GPT (P=0.03). However, in the multiple regression model, age and gender emerged as the most significant factors affecting GPT scores, and exposure to PCB/DDE was not significant. Performance on the SMST was not related to PCB/DDE exposure in initial unadjusted analyses, but performance with the dominant hand was marginally (P=0.052) associated with exposure in the final model. Scores on the SMST improved slightly as PCB/DDE exposure increased. A similar trend was not observed for the nondominant hand (P=0.46). These findings suggest that PCB/DDE exposure from Great Lakes fish has not significantly impaired hand steadiness or visual-motor coordination in this sample of older adults.

Age Factors↗